The present invention relates to communication systems, and in particular, to single wire communication systems and methods.
Devices that allow communication of information such as data or commands between electronic circuitry are known as communication systems. These systems are typically implemented on an integrated circuit where two or more terminals of the circuit are used to relay information. The information may be transmitted to or received from an operator, for example. The information may also be transmitted between other electronic devices within the system. There are typically two types of information sent and received: command information and data information. One example of command information is one component in a computer transmitting commands to another component. One example of data information is one component in a computer transmitting a number to another component.
Systems communicating in a digital format do so by transmitting a series of zeros and ones. The zeros and ones, also known as bits, are received by devices where they are decoded into useful information such as commands and data. Information within the system may be sent between devices through the process of encoding the information into a stream of bits. The method of encoding used to translate the bits may vary depending on the device. Typically, two digital devices that are coupled together share similar encoding and decoding schemes.
FIG. 1 illustrates an electronic circuit including a typical communication technique. A first terminal 120 may be used to receive commands while a second terminal 130 may be used to receive data. Some systems may also include additional terminals, such as third terminal 140, to send data, commands, or other information back to the transmitting electronic device. The method of sending commands, input data, output data, or other information varies between different communication systems. Typically, each piece of information may require a separate different terminal on the receiving or transmitting system.
With the ever increasing demand for more efficient and cost effective electronic devices, there is a desire to reduce the number of wires used for communications between electronic circuits. While electronic circuits are become smaller, the number of terminals on a circuit or pins on a packaged integrated circuit can limit the amount by which a circuit may be reduced in size. For example, when internal terminals are couple to pins on an integrated circuit package, each terminal is typically first coupled to a relatively large pad, which in turn is coupled to the package pin by bond wires. The pads are typically arranged around the perimeter of the integrated circuit, and in some cases may determine the size of chip (i.e., the perimeter of the chip must be large enough for the pads to sit side by side around the entire perimeter). Accordingly, reducing the number of communication wires can lead to lower costs because the number of pads and/or pins may be reduced.
Thus, there is a need for improved communication techniques. The present invention solves these and other problems by providing single wire communication systems methods.